In an electro-optical device using electrically controllable electro-optical substrates for the linewise output of picture information, the various optical electro-optical components must be precisely adjusted in relation to one another. German published patent application No. DE-OS 25 57 254 discloses an electro-optical device incorporating an electrically controllable electro-optical substrate made from a transparent electro-optical material, with the optical effect being controlled by applying a voltage between control electrodes; one control electrode is common to all picture points and the other is one of a plurality of individual electrodes, each capable of being separately connected to a control voltage. Particularly when a plurality of such substrates are to be joined end to end to provide the capability of simultaneously printing a long line of output, the precise adjustment of each substrate relative to the other components of the device becomes critical. However, the prior art did not provide a simple, accurate and reliable solution to the problem of being able to carry out the required adjustments.